I. Field
The following description relates generally to wireless communications and more particularly to interworking between radio access technologies.
II. Background
Interworking techniques between different Radio Access Technologies (RATs) can provide data session, voice call continuity, and fall back to circuit service even if a mobile device moves between different radio access technologies. Fall back refers to the situation where a mobile device user wants to make (or receive) a Circuit Switched (CS) call but the mobile device is on a technology that does not use the CS call. Therefore, mobile device has to “fall back” to a technology where the CS call is used and has to suspend a data session on the technology that does not use the CS call.
In accordance with some aspects, if the data session is not suspended, the data session is also moved to the technology where CS is used. Although interworking techniques can support fall back to circuit service, there are some cases where a target network does not support full functionalities that are supported in a source network. In that case, services can be continued, at least partially, by source network.
Switching technologies can create a problem if source network is not aware that mobile device has moved to target network (since these are independent paths). Thus, in some systems, mobile device, prior to changing networks, communicates to source network indicating that mobile device is going away for a certain duration of time. This notification procedure can produce delays that can negatively impact a user experience.